The present Invention relates to a sealing device, and in particular to a sealing device mounted on a piston.
As disclosed in Japanese Utility Model Laid-open No. 63-84459 published in 1988 without examination, opposite end portions of a sealing ring member are connected with each other in a halving joint manner. The fluid tight connection between the opposite end portions is expected to be established, after mounting the sealing ring on the piston which is movably fitted within a cylinder, by a fluid pressure in the cylinder which acts on the sealing ring along its radially outward direction and axial direction.
It is well known that with passing of time the sealing ring wears by friction and depending on the resultant frictional wear the radius of the sealing ring expands in the radial direction. This means that the engaging area between the opposite end portions becomes small which will affect the sealing function therebetween.